Since antiquity, ambergris has been highly valued in perfumery for its unique odor and fixative properties. However, due to a decline in the sperm whale population, ambergris is largely unavailable as an item of commerce. Consequently, the fragrance industry has great interest in synthetic odorants with amber-like properties. Ambergris and compounds possessing amber odors are extensively discussed by G. Ohloff, Chapter 15 in Fragrance Chemistry: The Science of the Sense of Smell, ed. by E. T. Theimer, Academic Press, 1982. Compounds that have strong amber or ambergris-like odors generally have bicyclic or tricyclic structures. For example dodecahydro-3a,6,6,9-tetramethylnaphtho[2,1-b]furan (I) possesses a strong amber odor (see M. Hinder and M. Stoll, Helv. Chim. Acta (1950) 33 1308).
.alpha.-Ambrinol (II) is an important synthetic amber odorant (see M. Stoll and M. Hinder, Helv. Chim. Acta. (1955), 38 1953). Compounds III and IV described by G. Ohloff et al., Helv. Chim. Acta (1976) 59 75 and ibid. (1973) 56 1414 also possess amber odors.
Recently U.S. Pat. No. 4,162,226 (1979) by D. Helmlenger and P. Naegeli describes compounds of structure wherein three of the R groups are methyl and one is hydrogen and one of the R.sub.1 is hydrogen an the other R.sub.1 is acetyl.
None of the prior art teaches nor indicates that the novel monocyclic compounds of the invention would possess valuable amber or woody amber-like odors. ##STR1##